Terraform: Indexing of computed lists does not work

[jszwedko]

Terraform Version

Terraform v0.7.3

Affected Resource(s)

n/a -- interpolation issue.

Terraform Configuration Files

provider "aws" {
  region = "us-east-1"
}

resource "aws_network_interface" "foo" {
  count = "3"
  subnet_id = "SUBNET ID"
}

resource "aws_route53_record" "aws_dns" {
  name = "test.com"
  count = 3

  zone_id = "ZONE ID"
  type = "CNAME"
  ttl = 30
  records = ["${aws_network_interface.foo.*.private_ips[count.index]}"]
}

Debug Output

https://gist.github.com/jszwedko/db8a5b43a61e7139fef6a195e1c588cb

Expected Behavior

A route53 record is created using the private IPs from the created network interfaces.

Actual Behavior

Refreshing Terraform state in-memory prior to plan...
The refreshed state will be used to calculate this plan, but
will not be persisted to local or remote state storage.


Error running plan: 3 error(s) occurred:

* At column 3, line 1: invalid index operation into non-indexable type: TypeString in:

${aws_network_interface.foo.*.private_ips[count.index]}
* At column 3, line 1: invalid index operation into non-indexable type: TypeString in:

${aws_network_interface.foo.*.private_ips[count.index]}
* At column 3, line 1: invalid index operation into non-indexable type: TypeString in:

${aws_network_interface.foo.*.private_ips[count.index]}

Steps to Reproduce

1. terraform plan
   

   Important Factoids

If you comment out the aws_route53_record, terraform plan and terraform apply you can than uncomment it and it creates correctly (now that the value it is indexing is no longer computed).

References

7906 is a related issue

[mitchellh]

Have a fix queued in the referenced PR!

[jszwedko]

Awesome!

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